microcode

mi·cro·code

M m

Transcription

- US Pronunciation
- US IPA
- [mahy-kruh-kohd]
- /ˈmaɪ krəˌkoʊd/

- US Pronunciation
- US IPA
- [mahy-kruh-kohd]
- /ˈmaɪ krəˌkoʊd/

Definitions of microcode word

noun microcode one or more microinstructions. 1
noun microcode the notation for writing microprograms on a given computer. 1
noun microcode A very low-level instruction set that is stored permanently in a computer or peripheral controller and controls the operation of the device. 1
noun Definition of microcode in Technology (programming) A technique for implementing the instruction set of a processor as a sequence of microcode instructions ("microinstructions"), each of which typically consists of a (large) number of bit fields and the address of the next microinstruction to execute. Each bit field controls some specific part of the processor's operation, such as a gate which allows some functional unit to drive a value onto the bus or the operation to be performed by the ALU. Several microinstructions will usually be required to fetch, decode and execute each machine code instruction ("macroinstruction"). The microcode may also be responsible for polling for hardware interrupts between each macroinstruction. Writing microcode is known as "microprogramming". Microcode may be classified as "horizontally encoded" or "vertically encoded". Horizontal microcode is as described above where there is a fairly direct correspondence between the bit fields in a microinstruction and the control signals sent to the various parts of the CPU. Not all combinations of bits will be valid (e.g. two units driving the bus at once). Vertical microcode is closer to machine code because a bit field value may pass through some intermediate combinatory logic which generates the actual control signals. This allows a few bits of a microinstruction to determine several control signals and ensure that only valid combinations of those signals are generated (e.g. a field may be decoded to determine which unit drives the bus). The disadvantage with vertical encoding is that the encoding is usually fixed and takes extra time compared with horizontal encoding which allows any combination of signals to be generated and takes no time to decode. The alternative to a microcoded processor is a hard-wired one where the control signals are generated directly from the bits of the machine code instruction. This is more common in modern RISC architectures because it is faster. Microcode is usually stored in ROM chips though some processors (e.g. the Orion) use fast RAM, making them dynamically microprogrammable. 1
noun microcode a set of microinstructions 0
noun microcode permanent basic commands built into a computer that enable its electronic circuits to perform operations 0

See all 6 definitions of microcode

Information block about the term

Parts of speech for Microcode

noun

adjective

verb

adverb

pronoun

preposition

conjunction

determiner

exclamation

Full grammatical hierarchy of Microcode

microcode popularity

A pretty common term. Usually people know it’s meaning, but prefer to use a more spread out synonym. About 62% of English native speakers know the meaning and use word.

According to our data about 60% of words is more used. This is a rare but used term. It occurs in the pages of specialized literature and in the speech of educated people.

microcode usage trend in Literature

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